domain

domain, in physics: see magnetism.

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domain

(1) In a LAN, a subnetwork made up of a group of clients and servers under the control of one security database. Dividing LANs into domains improves performance and security.

(2) In a communications network, all resources under the control of a single computer system.

(3) On the Internet, a registration category. See domain name and Internet domain name.

(4) In database management, all possible values contained in a particular field for every record in the file.

(5) A group of end points (phones or gateways) in a SIP telephony environment. See SIP.

(6) In magnetic storage devices, a group of molecules that makes up one bit.

(7) In a hierarchy, a named group that has control over the groups under it, which may be domains themselves.

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domain

1. land governed by a ruler or government

2. a region having specific characteristics or containing certain types of plants or animals

3. Austral and NZ a park or recreation reserve maintained by a public authority, often the government

4. Law the absolute ownership and right to dispose of land

5. Maths

a. the set of values of the independent variable of a function for which the functional value exists

b. any open set containing at least one point

6. Logic another term for universe of discourse (esp in the phrase domain of quantification)

7. Philosophy range of significance (esp in the phrase domain of definition)

8. Physics one of the regions in a ferromagnetic solid in which all the atoms have their magnetic moments aligned in the same direction

9. Computing a group of computers that have the same suffix (domain name) in their names on the internet, specifying the country, type of institution, etc. where they are located

10. Biology the highest level of classification of living organisms. Three domains are recognized: Archaea (see archaean), Bacteria (see bacteria), and Eukarya (see eukaryote)

11. Biochem a structurally compact portion of a protein molecule

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Domain (electricity and magnetism)

A region in a solid within which elementary atomic or molecular magnetic or electric moments are uniformly aligned.

Ferromagnetic domains are regions of parallel-aligned magnetic moments. Each domain may be thought of as a tiny magnet pointing in a certain direction. The relatively thin boundary region between two domains is called a domain wall. Within a wall the magnetic moments rotate from the direction of one of the domains to the direction in the adjacent domain.

A ferromagnet generally consists of a large number of domains. For example, a sample of pure iron at room temperature contains many domains whose directions are distributed randomly, making the sample appear to be unmagnetized as a whole. Iron is called magnetically soft since the domain walls move easily if a magnetic field is applied. In a magnetically hard or permanent magnet material a net macroscopic magnetization is introduced by exposure to a large external magnetic field, but thereafter domain walls are difficult to either form or move, and the material retains its overall magnetization.

Antiferromagnetic domains are regions of antiparallel-aligned magnetic moments. They are associated with the presence of grain boundaries, twinning, and other crystal inhomogeneities.

Ferroelectric domains are electrical analogs of ferromagnetic domains. See Antiferromagnetism, Ferroelectrics, Ferromagnetism, Magnetic materials, Magnetization, Twinning (crystallography)

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1.	(networking)	domain - A group of computers whose fully qualified domain names (FQDN) share a common suffix, the "domain name". The Domain Name System maps hostnames to Internet address using a hierarchical namespace where each level in the hierarchy contributes one component to the FQDN. For example, the computer foldoc.doc.ic.ac.uk is in the doc.ic.ac.uk domain, which is in the ic.ac.uk domain, which is in the ac.uk domain, which is in the uk top-level domain. A domain name can contain up to 67 characters including the dots that separate components. These can be letters, numbers and hyphens.
2.		domain - An administrative domain is something to do with routing.
3.		domain - Distributed Operating Multi Access Interactive Network.
4.	(mathematics)	domain - In the theory of functions, the set of argument values for which a function is defined. See domain theory.
5.	(programming)	domain - A specific phase of the software life cycle in which a developer works. Domains define developers' and users' areas of responsibility and the scope of possible relationships between products.
6.		domain - The subject or market in which a piece of software is designed to work.